Delirium: Is sleep important?

Abstract

Delirium and poor sleep quality are common and often co-exist in hospitalized patients. A link between these disorders has been hypothesized but whether this link is a cause and effect relationship or simply an association resulting from shared mechanisms is yet to be determined. Potential shared mechanisms include: abnormalities of neurotransmitters, tissue ischemia, inflammation, and sedative exposure. Sedatives, while decreasing sleep latency, often cause a decrease in slow wave sleep and stage REM sleep and therefore may not provide the same restorative properties as natural sleep. Mechanical ventilation, an important cause of sleep disruption in ICU patients, may lead to sleep disruption not only from the discomfort of the endotracheal tube but also as a result of ineffective respiratory efforts and by inducing central apnea events if not properly adjusted for the patient’s physiologic needs. When possible, efforts should be made to optimize the patient-ventilator interaction to minimize sleep disruptions.

Risk factors for postoperative delirium in patients after coronary artery bypass grafting: A prospective cohort study

“…However, the relationship between poor sleep and delirium remains unknown. In addition, authors have been uncertain that poor quality of sleep is a risk factor or outcome of delirium [33,34]. If poor sleep occurs, a consultation with an ICU physician might be indicated to initiate appropriate therapy, thereby improving clinical outcomes, including decreasing the incidence of delirium development [35].…”

Sleep Disruption at Home As an Independent Risk Factor for Postoperative Delirium

“…Delirium pathophysiology is understood broadly as the result of direct brain insults or other indirect acute stressors exceeding brain homeostatic mechanisms . Delayed or impaired sleep can cause disruption of the circadian rhythm, which has been associated with delirium . Rodent studies demonstrate that sleep disruption impairs innate immune defense, which may lead to the inflammatory dysregulation associated with postoperative delirium .…”

“…37 Delayed or impaired sleep can cause disruption of the circadian rhythm, which has been associated with delirium. 38,39 Rodent studies demonstrate that sleep disruption impairs innate immune defense, 40 which may lead to the inflammatory dysregulation associated with postoperative delirium. 41 Sleep, then, may contribute over the long term to the integrity of brain homeostatic mechanisms that enable resilience in the face of stressors such as surgery.…”

Sleep Neurobiology and Critical Care Illness

“…87 All these effects may play a role in the occurrence of delirium in ICU patients. 88 SUMMARY ICU patients experience severe sleep alterations with reductions in several sleep stages, marked sleep fragmentation, low sleep continuity, and circadian rhythm disorganization. The numerous sources of these sleep alterations are associated with disruptions of sleep neurobiological processes and sleep dynamics that could alter sleep restorative functions.…”